SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0cbc0b3e6fad148afcd719066eb73c259bbe1054523c63cee05ac2db7edcc2b' 
  AND token = 'bR8ShBp99b+2RCtHKvKow+sF0T6Egm8PkvLc+Juf7tI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}